Β-Thromboglobulin

β-Thromboglobulin (β-TG), or beta-thromboglobulin, is a chemokine protein secreted by platelets.^[1][2] It is a type of chemokine (C-X-C motif) ligand 7.^[3] Along with platelet factor 4 (PF4), β-TG is one of the best-characterized platelet-specific proteins.^[4] β-TG and PF4 are stored in platelet alpha granules and are released during platelet activation.^[1][4][5] As a result, they are useful markers of platelet activation.^[1][4] β-TG also has multiple biological activities, for instance being involved in maturation of megakaryocytes.^[6]

β-Thromboglobulin
Identifiers
Symbol	CXCL7
Alt. symbols	CTAP3, CXCL7, SCYB7, TGB1, THBGB1
NCBI gene	5473
HGNC	9240
OMIM	121010
RefSeq	NP_002695
UniProt	P02775
Other data
Locus	Chr. 4 q13.3
Search for Structures Swiss-model Domains InterPro

Biological actions

β-TG is a chemoattractant, strongly for fibroblasts and weakly for neutrophils. It is a stimulator of mitogenesis, extracellular matrix synthesis, glucose metabolism, and plasminogen activator synthesis in human fibroblasts.^[5]

β-TG also affects megakaryocyte maturation, and thus helps in regulating platelet production.^[5]

Clinical uses

Levels of β-TG is used to index platelet activation. It is measured by ELISA in blood plasma or urine, and often in conjunction with PF4.^[5]

Influences

β-TG levels may increase with age.^[7] It is elevated in diabetes mellitus.^[8]

β-TG levels have been found to be increased by treatment with the synthetic estrogen ethinylestradiol, though were not significantly increased by the natural estrogen estradiol valerate.^{[9][10][11][12]} Levels of β-TG have also been found to be increased or unchanged during normal pregnancy.^[13]